Telephone system



Nov. 5, 1946. Q J QSTLINE 2,410,520

' TELEPHONE SYSTEM v Filed July 26, 194; s Sheds-Sheet 1 ,u I Q Fl .I

I8 I [nsu/afzon 2s 49 2 L y 27 4 48 44. O 32 3| 29 3 25. n 4e 23 l2 s I la 17 I I 1 fl Z5 43 JOHN aosrum: K

ATTORNEYS Patented Nov. 1946 TELEPHONE SYSTEM John Ellis Ostline, Chicago, 111., assignor to Automatic Electric Laboratories, lino, a corporation of Delaware Application July 26, 1941, Serial No. 404,103

ular calling station one party line and for selecting the individually associated register for metering purposes. which arrangement is selectively governed by the calling devices *or dials at the various stations on the associated party line.

,More particularly, in this system, the switching apparatusis so connected and arranged that the preliminary digit 11" must be transmitted or dialed prior to the directory number oi the desired or called station in order to eflect operation thereof to extend a'call from any station on the party line. While this system is entirely satisfactory in operation, it requires the dialing of the preliminary digit 11" incident to the extension of a call from any station on the party line, resulting in slight inconvenience to the subscriber at the calling party station.

Accordingly, it is another object of the invention to provide in a telephone system of the type noted an improved arrangement for ident'i ing I the particular calling station on a party ine,

which arrangement requires the performance of no specialoperation or dialing of a preliminary digit on the part of the subscriber at the calling party station. Y

Another object of the invention is to provide in a telephone system of the type noted an improved arrangement for identifying the particular celling station on a party line, which is governed by the calling device at the calling party station incident to operation thereof to transmit the directory number of the-desired or called station.

6 Glaims. (Cl. 179-85) 2 adapted for use in the party station identifying arrangement of a telephone system of the type noted. r

A furtherobject of the invention isto provide an improved calling device which is of simple and compact construction and which is economical to manufacture and thoroughly reliable in operation. K

Further features of the invention' min t0 the particular arrangementmfi the mechanical elements of the calling device and of the circuit elements of the telephone system, whereby the above-outlined and additional feature are attained.

The novel features believed to be characteristic of the invention are set forth with particularity in theappended claims. The invention, both as to its organization and method of' operation, together with further objects and advantages thereof, willbest be "understood by reference to the following specification taken in connection with the accompanying drawings, in

which Fig. 1 is a, rear view of a; In: device embodying the present invention: Fig. 2 is a side elevationai view ofthe calling device own in Fig. 1; and. Figs. 3 and 4 taken together illustrate diagrammatically a. telephone system embodying the present invention.

Referring now more particularly to Figs. 1 and 2 of the drawings, there is shown a calling-device it of the finger dial type and of the general construction and arrangement of that. disclo in U. SJPatent No. 1,642,822, Herbert F. Obergiell. granted September 20, 1927, which has been modified to embody the present invention.

More particularly, t e calling device Become prises a casing ii, a rotatable arbor it, n gg r wheel or dial it secured to an enlarged s it provided on the outer end of thearbor i2; and a digits 1 to 0,,inclusive.

A further object of the invention is to provide in a telephone system of the type noted an im proved arrangement for identifying the particular calling station on a party line, which is selectlvely governed by improved calling devices disposed at the various stations on the associated party line.

A. further object 01 the invention is to provide an. improved calling device which is' specially cooperating finger stop it. The -er wheel it has ten spaced-apart openings therein, not shown. which are adapted to receive the finger oi the user and which respectively correspond to the provided in surrounding relation with the arbor ii; the inner end of the coil spring being secured to the casing ii and the outer end.

thereof being secured to the outer end of the arbor it. The rear wall oi" the casing it n a bracket ii, the bracket being secured in place by two spaced-apart. screws it. The bracket it carries a set of impulse springs it and it, a set of shunt springs 2t, 22 and it, and a set of o springs 2t and 25. I

-zTheinnerends oi the im springs it and Also, a coil spg itis' from the bracket I1 by a plurality of strips of insulating material 23 and are retained in clamped position by two screws 21. Also, the impulse springs I3 and 23 are respectively provided with electrical terminals 28 and 23. Similarly, the inner ends of the-shunt springs 2|, 22 and 23 are suitably insulated from each other and from the bracket I1 by a plurality of strips or insulating material 33 and are retained in clamped position by two screws. 3 I Also, the shunt springs 2i, 22 and 23 are respectively provided with electrical terminals 32, 33 and 34. Finally, the

inner ends of the cam springs 24 and 25 are suitably insulated from each other and from the bracket I1 by certain of the-strips of insulating material 33 and are retained in clamped position by the two screws 3i. The electrical terminal 23 are suitably insulated from each other and 33 is common to the shunt spring 22 and the cam spring 24; while the cam spring 26 is provided with an electrical terminal 35.

The cam spring 24 carries two spaced-apart and inwardly directed tabs 36 intermediate its 33 being clamped to the bracket II by the screws 3 I The arbor I2 carries a fixture 43 adjacent the outer end thereof and an annular insulating cam H on the extreme outer end thereof, the fixture 43 and the cam 4I being retained in place by a screw 42. The fixture 431s provided with snoutwardly extending impulse spring control arm 43 and an outwardly extending shunt spring control arm 44, the arms 43 and 44 being arranged in radially spaced-apart relation. The peripheral edge of the cam 4| carries one, two or three projections 43, three projections 43 being illustrated in the present example. The impulse spring 23 carries an insulating'control member 48 which cooperates with the control arm 43; and the shunt spring 23 carries an insulating control member 41 which cooperates with the control arm 44.

Further, the calling device 43 comprises mechanism, not shown, housed in the casing II, which includes a gear train and a connected impulse spindle 43 extending through an opening Ila provided in the rear "wall of the casing II. The outer end oi the impulse spindle 48 carries an impulse cam 43 which cooperates with the extreme outer end of the impulse spring I3.

When the finger dial I3 occupies its normal position the arbor I2 is biased in aclockwise direction, as viewed in Fig. 1, by the coil spring I8; whereby the control arm 43 carried by the fixture 43 engages the control member in order to urge the impulse springs I 3 and 23 into engagement, and the control arm 44 carried by the fixture 43 engages the control member 41 in order to urge the shunt springs 2 I, 22 and 23 into disengagement. At this point it is noted that the shunt spring 23 'is normally biased toward the shunt spring 22 due to its own resiliency. Also, the projections 45 carried by the cam M are di posed forwardly in a clockwise direction with respect to the outer end of the pawl 33; and the pawl 38 is biased in a connterclockwise direction about the pivot pin 31 by the leaf spring 33.

In order to operate the calling device I3, the user inserts his finger into one of the holes pro; vided in the finger wheel I3 corresponding to the IIO 4 digit to be transmitted and rotates the finger wheel I3 in a counterclockwise direction, as viewed in Fig. 1; until his finger engages the finger stop I5 and then releases the finger wheel I3. When the finger wheel I3 and the arbor I2 secured thereto are rotated in a counterclockwise direction, the coil spring I6 is wound and the mechanism housed in the casing I I is set to transmit the digit thus registered. More particularly, when the arbor I2 is rotated in a counterclockwise direction the control arm 43 carried by the fixture 43 disengages the control member 43, thereby to allow the impulse springs and23 to move, while maintaining engagement therebetween, to-

' ward and into cooperating relationship with respect to the impulse cam 43; however, the impulse spindle 48 and the impulse cam 43 carried thereby are not rotated prior to the release of the finger wheel I3. Also, when the arbor I2 is rotated in the counterclockwise direction thecontrol arm 44 carried by the fixture 43 disengages the control member 41, whereby the shunt spring 23 is moved into engagement with the shunt spring 22 and forces the shunt spring 22 into engagement with the shunt spring 2i due to the inherent resiliency of the shunt spring 23, as previously noted. Finally, as the arbor I2 is rotated in the counterclockwise direction, the projections 43 carried on the periphery [of the cam 4I ride over the outer end of the pawl 33 and therebehind. More specifically, when one of the projections 45 carried by the periphery of the cam 4i engagesthe outerend or the pawl 33, the pawl 33 is pivoted about the pivot pin 31. in a clockwise direction, -as viewed in Fig. 1, against the bias of the leaf spring 33; however, the cam spring 24 is not moved into engagement with the cam spring 2-3 due to this action 02 the pawl 38. When the projection 45 carried on the periphery of the cam 4i rides over the outer end of the pawl38 and therebehind the leaf spring 33 pivots the pawl 38. in the counterclockwise direction about the pivot pin 31 back into its normal position. without moving the cam' spring 24 into engagement with the cam spring At this time when the finger-wheel I3 is released it is returned in the clockwise direction,

as viewed in Fig. l, by the coil spring I3 back into its normal. position, whereupon the mechanism housed in the casing .I I rotates the impulse spindle 43 an appropriate amount corresponding to the digit registered. At this time, the outer end vof the impulse spring I8 is arranged in coopthe impulse spring I3 is moved out of engage-' ment with the impulse spring 23. Hence, the opposite ends of the impulse cam 43 alternately engage and disengage the outer end of the impulse spring I3, thereby alternately to move the imimpulse springs I3 and 23 corresponding to the digit registered. Also, when the finger wheel I3 is released the cam 4I carried on the outer end of the arbor I2 is rotated in a clockwise direction, as viewed in Fig. 1,.whereby the projections. carried on the periphery of the cam 4i alternately engage a disengage the outer end of the pawl 38. More particularly, when one of the projections 48 carried on the periphery of the cam engages the rear surface ofthe outer end of the pawl "the sequently, when the projection 35 carried on the periphery of the cam 4| rides over the outer ends of the pawl 38, the pawl 38 and the cam spring j 24 are returned to their normal positions due to the inherent resiliency, of the cam spring 2d, whereby the cam spring 2% is moved into disengagement with the cam spring 25. j Accordingly, as the arbor i2 is rotated in the'clockwise direction back into its normal position theprojectlons 65 on the periphery of the cam 4! cause the cam springs 26 and 25. tooperate into engagement and disengagement a like number of times, whereby the calling-device iii transmits a number of impulses byway of the cam springs 26 and 25 corresponding to the number of projections as provided on the periphery of the cam ti.

Just prior to the time the arbor i2 is rotated in the clockwise direction completely back into its normal position, the control arm is carried by the fixture it engages the control member it carried by the impulse spring 20 and forces the impulse spring 20 away from the impulse cam 59, whereby the outer end of the impulse spring i9 is forced out of cooperating relationship with respect to the impulse cam'tQ in order to prevent any further operation of the impulse cam ts from operating the impulse spring it. Ultimately. when the arbor I2 is rotated-in the clockwise direction into its final normal position, the control arm M carried by the fixture 68 engages the control member 31 carried by the shunt .spring 23; whereby the shunt spring 23 is forced out of engagement with the shunt spring 22 and the shunt spring 22 is forced out of engagement with the shunt spring 2!, due to its inherent resiliency. Also, when the arbor i2 has'been rotated in the clockwise direction to its final normal position, the last projection d5 carried on theperiphery of the cam 61 has operated the as- "sociated pawl 38, in the manner explained above.

' have been transmitted by way .of the impulse springs i9 and 2d a slight time interval prior to the final return of the finger wheel is and the connected arbor it into their normal positions. Also, it is noted that the shunt springs 28, 22 and 23 are moved into disengagement only upon the final return of the finger wheel it and the connected arbor l2 into their normal positions; while the last projection d5 provided on the periphery of the cam dl operates the associated pawl 38 just prior to the final return of the finger wheel l3 and the connected arbor i2 into their normal positions. The cooperation between the elements 2i, 22 and 23 are operated into engagement at all times when the finger wheel I3 is away from .its normal position; while the finger wheel 13 must be moved a predetermined distance from its normal position in order to cause the first digit 1 to be eilectively registered in the mechanism housed in the casing ll. Also, the cooperation between the elements mentioned above permits control of the cam springs 26 and 25 to send one impulse in excess of the'number of impulses in the digit registered in the mechanism housed in the casing it when the digits 1 and 2 are 'registered therein. By way of illustration, it is'pointed out that, in the present embodiment of the callis the mechanism housed in the casing ii, in order to cause the impulse springs i9 and to be controlled to transmit two impulses. the cam springs 2d and are controlled to transmit three impulses, three projections at being provided on the periphery of the cam dl. Further, it will be understoodthat the number of projections proi vided on the cam t5 may be varied in order to obtain selective control-of the associated switching apparatus; however, in the present embodiment it is contemplated that the cam M will have no projections as thereon or 1, 2 or 3 projections thereon," thereby rendering the calling de vice l0 capable of four modifications, inan obconjunction with the telephone system in which the calling device it is incorporated.

Finally it is noted that .the cooperation between the elements mentioned above is such that the impulses transmitted by way of the cam springs 2 and 25 and the impulses'transmitted by the impulse springs l9 and 2d are transmitted alternatively. In the present example, when any digit between ,Z'and 0 is dialed the camjsprings then the impulse springs 19 and 2t operate to transmit their first impulse; then the cam springs 2t and 25 operate to transmit their'second impulse; then the impulse springs iii and 2t operate to transmit their second impulse; and then the cam springs E i and 25 operate to transmit their third impulse. Thereafter, the impulse springs is and 2d are operated to transmit their third, etc., impulses in the event the digit dialed so is 3, etc.; however, the cam springs 2d and 25 are not operated to transmit further impulses.

Also it is pointed out, that the selective control of the cam springs 24 and 25 may be eilected merely by suitably adjusting the normal position of the cam ti upon the outer end of the arbor 82 with reference to the pawl 8t, instead of substituting diflerent cams iii having different numbers of projections ti on the peripheries thereof, as explained above.' 7 00 Referring now more particularly to Figs. 3 and 4 of the drawings, the telephone system there illustrated comprises an exchange having a plurality of individual subscriber lines, not shown, terminating thereat, and a plurality of party subscriber lines,including the party subscriber lines tilt and 8%, terminating thereat, and provided with switching apparatus. Each of the party subscriber lines has four party subscriber substations individually associated therewith; the party subscriber substations till, 302, the and 3% being. individually associated with the party subscriber line lit, and the party subscriber substations Whtw, tit and 314 being individually associated with the party subscriber line are. Each party subscriber substation comprises subing device it, when the digit 2 is registered 'in vious'manner', as will be explained more fully in 2d and 25 operate to transmit their first impulse;

station apparatus, including a harmonic ringer, the four harmonic ringers at the four party subscriber substations on each party subscriber line being respectively tuned to 16, 33, 50 and 66 cycle. ringing currents. In the present exampie, the party subscriber substations 3M, 302, 303 and 304 connected to the party subscriber line I30 and the party subscriber substations 3i I, 3I2,'3I3 and 3 connected; to, the party subscriber line I20 are respectively 16, 33, 50 and 66 cycle substations.

Preferably, the substation apparatus provided at each party subscriber substation is substantially identical to that provided at the fourth party subscriber substation 304 connected to the party subscriber line I30, with the exception of certain modifications in the calling devices thereat, as noted more particularly below. The

substation apparatus provided at the fourth party subscriber substation 304 comprises a harmonic ringer IN, a transmitter I02, 2. receiver I03, a hook switch SIM, an inductioncoil I0? and a calling device I0, the calling device I0 being identical to that disclosed in Figs. 1 and 2 of the drawings and including a cam 4Iprovided with three projections 45 on its periphery. The substation apparatus provided at the first, second and third party subscriber substations 30I, 302 and 303, respectively, is substantially identical to that provided at the fourth party subscriber substation 304, except that inthe calling devices respectively provided at these party subscriber substations, the cam 4i comprises no projections 45, one projection 45 and two projections 45. In view of the fact that the calling devices provided at the first party subscriber substations 30I, 3| I,

etc., each comprise a cam 4i provided with no projections 43 thereon, the calling device provided at each first party subscriber substation may be of conventional construction and arrangement' and of the character of that disclosed in the previously mentioned Obergfell patent, wherein the cam 4I andthe set of cam springs 24 and 25 are eliminated.

The switching apparatus provided in the exchange comprises a plurality of individual line switches of conventional connection and an rangement, not shown, individually associated with the individual subscriber lines, not shown, and a plurality of party line switches, including the party line switches 320 and 330. individually associated with the party subscriber lines, the line switches 320 and 330 being respectively individually associated with the party subscriber lines I30 and I20. Also. this switching apparatus comprises a plurality of meter switches 350,- 310,

etc., individually associated with the party line" switches 320, 330, etc., which are, in turn, individually associated with the party subscriber lines I30, I20, etc. Further, this switching apparatus comprises a group of regular selectors, not shown, a group of repeater selectors, including the repeater selector 400; a group of special service selectors, including the special service selector 408, four groups of individual connectors, not shown, and four groups of party connectors. The first, second, third and fourth groups of party connectors respectively include the party connectors 40I, 402, 403 and 404, which party connectors respectively ring a line seized thereby with 16, 33, 50 and 66-cycle ringing currents.

Further, the exchange comprises a manual operator position 0; a toll operator position H0, and a plurality nI' iniaSilied service meters individually associated with the party subscriber substations. More particularly, the meters M305,

M308, M301 and M308 are respectively indi-,

vidually associated with the party subscriber subindividually associated with the party subscriber substations 3II, 3I2, 3l3- and 3I4. Finally, the exchange comprises a group of repeaters, including the repeater 400.

The apparatus in the exchange is so connected and arranged that each of the individual line switches has access to the group of regular selectors; while each of the party line switches 320, 360, etc., has access to each of the repeaters 400, etc., by way oi incoming trunks, 4I0,,etc., individual to the repeaters 400, etc. Each repeater 400, etc., in the group is directly connected by way of an outgoing trunk 480, etc., individual thereto to a corresponding one of the repeater selectors 405, etc., in the associated group. Each meter switch is individually associated with one of the party line switches and has access to the four meters respectively individually associated with the four party subscriber substations connected to the party subscriber line with which the party line switch is individually associated. By way of example, it is noted that the meter switch 350 is individually associated with the party lineswitch 320 and has access to the four meters M305, M306, M301 and M303 respectively individually associated with the four party subscriber substations SM, 302, 303 and 304 connected to the party subscriber line I30 with which the party line switch 320 is individually associated.

Each of the regular selectors in the group and each of the repeater selectors in the group have access to the group of special service selectors, to the four groups of party connectors, to the four groups ofindividual connectors, and to a group of trunks extending to the manual operator position 0. Each of the individual connectors in each of the groups has access to each of the individual subscriber lines; each of the party connectors in eachoi. the groups has access to each of the party subscriber lines; and each of the special service selectors in the group has access to a group of trunks extending to the toll operator position IIO.

Preferably, each of the individual line switches is of conventional connection and arrangement; while each of the party line switches is identical to the party line switch 320. The party line switch 320 comprises a switching mechanism, in cluding a rotary wiper set provided with five wipers'32i, 322, 323, 324 and 325, an associated contactbank, and a rotary magnet M320 for driving the wiper set noted. Also, the party line switch 320 comprises a relay network including a cutoff relay R330 and a line relay R340.

Preferably, each of the meter switches is identical to the meter switch 350 which comprises a switching mechanism including a rotary wiper set provided with a single double-ended wiper 35I, an associated contact bank, and a rotary magnet M352 for driving the wiper set noted.

Also, a set of switch springs S354 is associated with the wiper set of the meter switch 380 and operated, in a manner more fully explained hereinafter. I

Preferably, each of the repeaters is identical to the repeater 400 which comprises a relay network, including a digit cutoff relay R4I0, a meter relay R420, a dial relay R430, an answer relay new, a line relay Run, a hold relay am and typ each of the special service selectors 486, etc.,

is of the conventional drop-back Strowger type; and the manual operator position a and the toll operator position H comprise conventional operator position equipment.

In accordance with the trunking plan incor-.

porated in the telephone system, both the regulator selectors and the repeater selectors have gages an associated contact set at each step of the party line switch 320. Accordingly, at this time, the idle or busy condition of the incoming trunk. terminated by the engaged contact set and extending to one of the repeaters is tested.

- ,In the event the last-mentioned trunk extends access to the group of special service selectors in the first level of the associated contact banks, to the first, second, third and fourth groups of party connectors in the respective second, third, fourth and fifth levels or the associated contact banks, to the four groups of individual connectors in the sixth, seventh, eighth and ninth levels to a busy repeater, ground potential appears upon the control conductor thereof andis applied to the control wiper 323 of the wiper set, thereby to complete a path, including the contacts 385, 3H and 3&2, for, short-circuiting the winding of the cutoff relay R330, and to complete a low resistance circuit, including the contacts 335, 8M and 321, for energizing the'ro'tary magnet M326. When the rotary magnet M326 is thusenergized it operates, thereby-to condition the wiper set to be driven one step in the rotary direction and .to interrupt, at the contacts 321, the previously traced circuit for energizing the rotary magnet of the associated contact banks, and to the group of trunks extending to the manual operator position d in the tenth level of the associated contact banks.

The connection and arrangement of the system will best be understood from a consideration of the following description,. with reference to Figs.

- 3 and 4 of the drawings, of the operation of the apparatus incorporated therein to set up the dif ferent connections between the various indi vidual and party subscriber substations.

Considering now the extension of a call from the fourth party subscriber substation tilt, con

nected to the party subscriber line lit, to the first party subscriber substation 3, connected to the party subscriber line lid, the call is first initiated at the fourth party subscriber substation 3 by removing the receiver Hid from its associated switchhook, thereby to operate the hoolr switc h Side. When the hook switch sacs is thus operated there is completed, at the contacts the and the thereof, obvious operative connections between the transmitter let, the receiver m3 and the party subscriber line tilt; whereby a circuit iscompleted for energizing the winding of the line relay Rt id in the party line switch did inof the party subscriber line Still, the primary "winding of the induction coil idi, the transmitter N2, the contacts ltd of the hook switch Site, the impulse springs it'and it of the callin M328. The rotary magnet M325 then restores, thereby to drive the wiper set one step in the rotary direction and torecomplete, at the contacts 32?, the previously mentioned circuit, ineluding the test wiper 323 of the wiper set, for testing the idle or busy condition of the trunk terminated by the contact set engaged by the wiper set at this time. On the other hand, in the event the wiper set engages a contact set terminating an idle trunk, no ground potential appears upon the control conductor thereof, whereby the previously traced test circuit, including the test wiper 328 and the rotary magnot meet, is not completed. Accordingly, the previously traced low resistance circuit for energizing the rotary magnet M326 is not completed and the previously traced path for shortcircuiting the winding of the cutod relay Reed is not completed. Hence, when operation of the party line switch 320 is initiated the wiper set is driven a step in the rotary direction only in the event that it engages a contact set tern inst:- ing a busy trunk, in which event the wiper set is driven step by step in the rotary direction until it engages a contact set terminating an idle trunk.

Assuming that the wiper set of the party line switch 32% engages the contact set terminating cluctor (3518 of the trunk did. Accordingly, the

previously traced low resistance circuit, includ device iii, the line conductor Cid! of the party subscriber line Add, the contacts 33! and the winding of Rdid to battery.

When thus energized the line relay Ride operates to complete, at the contacts 382, an obvione path for applying ground potential to the control conductor Cite of the party subscriber line iilii in order to'marlr the party subscriber line ltd as busy to the party connector switches ing the control wiper 3%,for energizing the ro tarymagnet Middle not completed; and the pre viously traced path, including the control wiper 323, for short-circuitingthe winding of the cutoff relay Rite is not completed. Hence, .at this time, an obvious circuit, including the contacts 3% and 327, is completed for energizing in series the winding of the cutoff relay Rddd and the "line relay Rt iii, thereby to cause the latter relay to restore shortly thereafter, the line relay Rdtd being of the s'lcw-to-release type. Also, the cut= ofi' relay Rees completes, at the contacts 332 and 33 3, a circuit for energizing in series the upper winding of the line relay Redd andthe upper and lower windings of the meter relay Rim) in the repeater 400, this circuit extending from ground by way or the contacts 442-, the lower winding of R420, the line conductor C412 of the trunk 410, the line wiper 322, the contacts 334, the line conductor CI32- of the party subscriber line I30, the primary winding of the induction coil I01, the transmitter I02, the contacts I oi the hook switch SI04, the impulse springs I9 and 20 of the calling device I0, theline conductor CI3I of the party subscriber line I30, the contacts 332, the line wiper 32I, the line conductor C4'lI of the trunk 4l0, theupper winding of R420 and the upper winding of R450 to battery. When this series circuit is completed the line relay R450 operates; however, the meter relay R420 does not operate as it is of the differential type.

Further, the cutoff relay R330 interrupts, at the contacts 335, the previously traced test circuit between the control wiper 32 3 and the rotary I magnet M326; and completes, at the contacts 336,

traced hereinafter for energizing the rotary magnet M352 of the meter switch 350; prepares, at

completes, at the contacts 46I, a loopcircuit extending between the repeater 400 and the repeater selector 405 individually associated with the repeater 400. This loop circuit extends from the line conductor C48I of the trunk 400 by way of the contacts 40I, the impedance 4I5, the

left-hand winding of the answer relay R440 and,

the contacts I to the line conductor C482 01 the trunk 080, the line conductors C43I and C402 of the trunk 430 being connected by way of the apparatus in the repeater selector 405 respectively to battery and ground potentials,

' whereby the repeater selector 405 is conditioned to be responsive to a digit transmitted thereto. When the repeater selector 405 is thus conditioned to be responsive to a digit transmitted thereto, ground potential therein is applied to the control conductor C483 of the trunk 480; and is returned therefrom by way of the control conductor C413 of the trunk 410 to the control wiper 323. This application of ground potential tothe control wiper 323 completes an obvious holding circuit for energizing in series the winding of the cutoff relay R330 and the rotary magnet M320 in the party line switch 320. At this point, it is noted that .the above-mentioned holding circuit is completed prior to the restoration of the line relay R340 in order to prevent the release of the party line switch 320. Shortly after the above-mentioned holding circuit is completed the line relay R340 restores in order tointerrupt, at the contacts 3, a further point in the previously mentioned test circuit, including the control wiper 323 and the rotary magnet M028; and t0 12 interrupt, at the contacts 342, the original operating circuit for energizing in series the winding of the. cutoff relay R330 and the rotary magnet M325. Also, it is noted that at this time ground potential appearing upon the control conductor C413 of the trunk 410 is returned by way of the control wiper 323 and the contacts 330 to the control conductor CI33 of the party subscriber line I30, thereby to retain the party subscriber line I30 marked as busy to the party connectors windings of the answer relay R440 are thus energized this relay does not operate, as it is of the polarized type. Accordingly, at this time an operative connection is completed between the fourth party subscriber substation 304, connected to the party subscriber line I30, and the repeater 400 by way oi the party subscriber line I30, the

' party line switch 320 and the trunk 410; also, the

repeater400 is operatively ,connected to the repeater selector 406 by way of the trunk 480. Further, dial tone current is returned from the repeater selector 40.5 by way of the above-traced connection to the receiver I03 at the fourth party subscriber substation 304 in order to indicate to the subscriber thereat that he may proceed to dial the first digit of the directory number.

The subscriber at the calling fourth party subscriber'substation 304 then proceeds to dial the first digit of the directory number of the called first party subscriber substation M I, the directory number of the called first party subscriber substation 3II being 2m, such, for example, as 234. When the subscriber at the calling fourth party subscriber substation 304 pulls the finger wheel of the calling device I0 in accordance with the digit 2, the shunt springs 2!, 22 and 23 are operated into engagement; the mechanism housed in the casing of the calling device I0 registers the digit 2; and the cam 4Iis rotated in a counterclockwise direction, 'as viewed in Fig. 3, in order to move the three projections 45 carried on the periphery thereof behind the associated pawl 38, in the'manner previously explained. When the shunt springs 2|, 22 and 23 are operated into engagement, an obvious path is completed for shortcircuiting both the transmitter I02 and the receiver I03, in accordance with conventional practice; and a direct dialing bridge, including the primary winding of the induction coil M1, the shunt springs 23' and 22 and the impulse springs I9 and 20. is completed between the line conductors CI32 and CI3I of the party subscriber line I30.

The subscriber at the calling fourth party subscriber substation 304 then releases the finger wheel of the calling device i0, whereby the calling device I0 operates, in the manner previously explained, in coniunctionwith Figs. 1 and 2 of the drawings. More particularly, the cam springs 24 and '20 operate to transmit a first ground impulse over the line conductors CI3I and CI32 of the party subscriber line I30 prior to the operation of the impulse springs I0 and 20 to interrupt the previously traced loop circuit extending bel3 I tween the calling fourth party subscriber substation 305 and the repeater W, in the manner previously explained. The path for applying ground potential to the line conductor C13! extends from ground by way of the cam springs 25 and 2d, the shunt spring 22 and the impulsesprings it and to the line conductor Cl3i;'-

circuit for energizing thelower and upper windwhile the path for applying ground potential to -the hold relay R460; however, the latter relay the line conductor (.182 extends from ground by way of the cam springs and 25, the shunt springs 22 and 23 and the primary winding of theinduction coil I01 to the line conductor C132. The application of ground potential to the line conductor Cltl oi the party subscriberline I completes an alternative circuit substantially identical to that previously traced for energizing in series the upper winding of the meter relay R428 and the upper winding of the line relay R65!) in the repeater eon; while the application of ground potential to the line conductor (SE32 of the party subscriber line I30 completes a path, including the contacts 336, the line wiper 322,

the line conductor CW2 of the trunk M0 and the contacts ear for short-circuiting the lower winding of the meter relay R420. Accordingly, the line relay Refit remains in its operated position while the meter relay R6213 operates, the latter relay being of the differential type and the lower winding thereof being short-circuited at this time.

Upon operating, the meter relay Rtfid completes,

at the contacts can, a circuit, including the contacts it i, the conductor Celt oiithe trunk tit, the wiper 82d and the contacts sec, for energizing the magnet Midi of the meter switch 350. When thus energized the magnet M352 operates in order to condition the wiper set to be driven one step in the clockwise direction away from its home position.

Upon complete operation of the cam springs 2d and 25 to transmit the first ground impulses, ground potential is removed from the line conductors Cit! and C532 of the party subscriber line itii, whereby the previously traced path for short-circuiting the lower winding of the meter relay Riiiii is interrupted and the previously traced circuit for energizing in series the lower and upper windings of the meter relay Refit and the upper-winding of the line relay Witt is recompletedv When both the upper and'lower windings of the meter relay R i'iti are thus energized this relayrestores as it is of the difierential type, as previously noted; also, at this time, the line relay nose retains its operated position. Upon restoring, the meter relay Rees interrupts, at

for energizing the rotary magnet M352 thereby ings of the meter relay R420 and the upper winding ofthe line relay R458 is recompleted, thereby to cause the meter relay R428 to retain its restored position and to cause the line relay R450 to reoperate. Upon restoring, the line relay R650 interrupts, at thecontacts 452, the previously mentioned circuit for energizing the winding of does not restore at this time as it is of the slow-' to-release type. Also, the line relay R450 completes, at the contacts 453, anobvious circuit, including the contacts $63; for energizing the winding of the dial relay R430, thereby to cause the latter relay to operate. Upon operating, the dial relay R430 completes, at the contacts til, an obvious path for short-circuiting the impedance element t [5 and the left-hand winding of the answer relay Rttt, thereby to provide a low resistance bridge across the line conductors Ctfli and C i82 of the trunk $80 and positively to prevent operation of the answer relayRttO incident to switching surges impressed upon the trunk 480 incident When the lower winding of the digit cutoff relay Rd!!! is thus short-circuited' it will not take a second stp to interrupt, at-the contacts M I, a

prepared point in the previously traced circuit for energizing the rotary magnet M352 of the meter switch 350. Also, upon restoring, the line relay Rttt interrupts, at the contacts 65!, the

previously traced loop circuit extending between the repeater tilt and the repeater selector its.

Upon reoperating, the line relay R 350 recompletes, at the contacts can, the previously mentioned loop circuit extending between the repeater see and the repeater selector-dds, recompletes, at the contacts ear, the previously mentioned circuit for energizing the winding of the hold relay R068, and interrupts, at the contacts 353, the previously traced circuitior energizing the windingof the dial relay with; however, the

til)

to cause the rotary magnet M352 to restore;

whereupon the wiper tel-of the meter switch 35% is driven one step in the clockwise direction away from its home position. Y

The impulse springs i9 and 2d of the calling device iii are then operated to transmit the first impulse, whereby th previously mentioned loo circuit extending between the calling fourth party subscriber substation tilt and the repeater are dial relay B itt does not immediately restore as it is'of the slow to release type. At thispoint, it is noted that neither the hold relay Redd nor the dial relay Rtiiu restore during impulsing; both of these relays being of the slow-to-release type, as previously noted. The first restoration and reoperation of the line relay Rttt is effective to transmit an impulse over the trunk tee to the repeater selector 6%, thereby to cause the repeater selector tilt to take one step in the vertical direction,- in an obvious manner.

During the subsequent operation ofthe calling device it the cam springs 26. and 2E operate to transmit their second ground impulse; thenv the im ulse springs i9 and 2t operate to transmit is interrupted and thenrecompleted, in an obvi ous manner. When the previously mentioned loop circuit is interrupted the series circuit for energizing the lower and upper. windings of the meter relay Edit and the upp r winding of the line relay Met is interrupted, thereby to cause the meter relay RtZd to retain its restored position and to cause the line relay Rttt to restore. Subsequently, when the above-mentioned loop circuit is-recom'pleted the previously traced series their second impulse; and, finally, the cam springs to and iii operate to transmit their third ground impulse; at which time the finger wheel of the calling device it is returned to its normal position and the first digit 2 has been transmitted therefrom. The second and third ground im-- pulses transmitted by the cam springs 2t and 2b oi the calling device It cause the meterrelay am to operate and then restore two additional times; whereby the meter relay Rita is operated and then-restored three times incident to the opl eration of'the calling device I0 to transmit the digit 2, in the-manner explained above. This operation of the meter relay R420 causes the wiper 35I of the meter switch 350 to be advanced three steps away from its normal position in the clockwise direction, in the manner explained above. The second impulse transmitted by the impulse springs I9 and 20 of the calling device I0 causes the line relay R450 to restore and reoperate one-additional time; whereby the line relay R450 is restored and then reoperated twice incident to the operation of the calling device I0 to transmit the digit 2, in the manner explained above. This operation of the line relay R450 causes the digit 2 to be transmitted over the trunk 480 to the repeater selector 405, in the manner explained above.

The repeater selector 405 responds to the first digit 2 transmitted thereto to advance its wiper set two steps in the vertical direction; whereupon the wiper set thereof is operated automatically in the rotary direction to select an idle party connector in the group, including the party connector 40I, in an obvious manner. Assuming that the party connector MI is seized by the repeater selector 405, the party connector MI is then conditionedto be responsive to the second and third digits 3 and 4, respectively, in accordance with conventional ractice.

At the conclusion of the first digit 2, the line relay R450 reoperates, thereby to interrupt, at the contacts 453, the previously traced circuit for energizing the winding of the dial relay R430,

whereupon the latter relay restores'shortly thereafter as no further restoration of the line relay R450 occurs until the subscriber at the calling fourth partly subscriber substation 304 dials the second digit 3. Upon restoring, the dial relay R430 interrupts, at the contacts 433 ,-the previously traced path for short-circuiting the lower ther point in the previously traced circuitfor energizing the rotary magnet M352.

At this time, the wiper of the meter switch 350 has been operated three steps in the clockwise 'direction away from ,its normal position, thereby to prepare a circuit traced hereinafter for operating the meter M308 individually associated with the fourth party subscriber substation 304 connected to the party subscriber line The subscriber at the calling party subscriber substation 304 then proceeds to dial the second digit 3, thereby to cause the line relay R450 to restoreand reoperate three times in order to transmit the three impulses of the second digit over the trunk 480 and the repeater selector 405 to the party connector 40 I. Incident to the dialsecond digit 3, is without effect due to the fact that the digit cutoff relay R4I0 occupies its fully operated position at this time, as the last-menparty subscriber substation 304 proceeds to dial the third digit 4, thereby to cause the line relay R450 to restore and reoperate four times in order to transmit the four impulses of the third digit over the trunk 480and the repeater selector 405 to the party connector 40L Also, in-

cident to the dialing of the third digit 4, the

meter relay R420 operates and restores three times; however, this operation of the meter relay R420 is without effect due to the fully operated position of the digit cutofl relay R 4I0. In v view of the foregoing explanation of the operation of the meter relay R420, incident to the dialing of the second and third digits, it will be understood that this relay is effective to control the setting of the meter switch 350 only incident to the dialing of the first digit of the directory number, due to the full operation of the digit cutoff relay R4I0 at the conclusion of the first digit of the directory number.

The party connector 401 responds to the second digit 3 and the third digit 4 in accordance with conventional practice inorder to seize the partly subscriber line I20. Upon seizing the party subscriber line I20, the party connector 40I tests the-idle or busy condition thereof; whereupon busy tone current is returned over the repeater selector 405, the trunk 480, the repeater 400, the trunk 410, the party line switch 320 and the party subscriber line I30 to the calling fourth party subscriber substation 304 in the event the called party subscriber line I20 is busy at this time. On the other hand, in the event the called party subscriber line I20 is idle at this time, the party connector 40I operates in order to ret rn ring-back tone current over the previously traced connection to the calling fourth party subscriber substation 304 connected to the party subscriber line I30; and to project 16 cycle ringing current over the called party subscriber line I20. The 16 cycle ringing current projected over the called party subscriber line I20 causes operation of only the harmonic ringer at the called first party subscriber substation 3H connected to the party subscriber line I20 due to the fact that the harmonic ringers disposed at the second, third and fourth subscriber substations 8I2, 3I3 and 3I4, respectively, connected to the party subscriber line I20, are respectively tuned to ringing currents having the respective frequencies of 33, 50 and 66 cycles.

The subscriber at the called first party subscriber substation 3I I, connected to the party subscriber line I20, answers the call by removing the receiver of the telephone instrument thereat from its associated switchhook, thereby to complete an obvious operative connection, including the party subscriber line I20, between the first party subscriber substation 3H and the party connector 40l. When this connection is completed the party connector 40] operates in order to reverse battery over the repeater selector 405 and the loop circuit extending between the repeater selector 405 and the repeater 400. When battery is thus reversed over the above-mentioned loop circuit the left-hand winding of the answer relay R440 is energized in the opposite direction, in an obvious manner, whereupon the answer relay R440 operates. Uponoperating, the answer relay R440 interrupts, at the contacts 442, the previously tramd circuit for energizing in series operated at the conclusion the lower and upper windings of the meter relay R420 and the upper winding of the line relay R450; and completes, at the contacts 44!, an obcompletes, at the contacts 443, a circuit includ- -ing the conductor C415 of the trunk 410, the

wiper 325 of the party line switch 320, the contacts339 and the wiper 35I and engaged fourth contact in the associated contact bank of the meter switch 350 for operating the meter M308 individually associated with the fourth party subscriber substation 304, connected to the party subscriber line I30 in order to register the completion of a call from" the lastmentioned party subscriber substation.

At this time, the previously traced loop circuit extending between the calling fourth party subscriber substation 304, connected to the party subscriber line I30, and the repeater 400 is completed; the previously traced loop circuit extendlag between the repeater 400 'andthe party connector 40I is completed; and the previously mentioned connection extending between the called first party subscriber substation 3, connected to the party subscriber line I20, and the party 18 repeater 400 restores and the'repeater selector 405 is released in order to effect the release of the party connector 40I. When the repeater selector 405 is thus 'released the application of ground potential is removed from the control conductor C483 of the trunk 430, thereby to interrupt the previously traced holding circuit for energizing in series the winding of the cutoff relay R330 and the rotary magnet M326 in the connector MI is completed. Finally, it is noted that an operative connection between the trunk 410 incoming to the repeater 400, and the trunk 480 outgoing from the repeater 400, is completed by way of the condensers 4I3 and 4I4. Hence, an established connection is completed between the calling fourth party subscriber substation 304, connected to the party subscriber line I30, and the called first party subscriber substation 3I I, connected to the party subscriber line 420, for two-way communication purposes.

The release of the established connection between the calling fourth party subscriber 'substation 304, connected to the party subscriber line I30, and the called first party subscriber substation 3| I, connected to the party subscriber line I20, is primarily under the control of the sub-' scriber at the calling fourth party subscriber substation 304, and is accomplished when the subscriber thereat replaces the-receiver I03 upon party line switch 320, in order to cause the latter relay to restore.

Upon restoring, the hold relay R460 interrupts, at the contacts 464, the previously traced circuit for energizing in series the upper and lower windings of the digit cutoff relay R4I0, thereby to cause the latter relay to restore. Also, upon restoring, the answer relay R440 interrupts, at the contacts 443, the previously traced 'circuit for energizing the meter M308 individuallyassociated with the fourth party subscriber substation 304, connected to the party subscriber line I30. At this time the repeater 400 is completelyv released and is marked as idle to the party line switcheshaving access thereto by the'absence of potential upon the control conductor C413 of the trunk 410.

Upon restoring, the cutoff relay R330 in the party line switch 320 interrupts, at the contacts 330, a further point in the previously traced circuit for energizing in series the winding of the cutoff relay R330 and the rotary magnet M326, and completes, at the contacts 331, an obvious circuit including the set of switch springs S354 and the contacts 353 for energizing the rotary magnet M352. At this point it is noted that the set of switch springs S354 is actuated into engagement when the wiper 35I of the meter switch 350 'is rotated in the clockwise direction away from.

its home position. When thus energized the rotary magnet M352 operates to interrupt, at the contacts 353, the previously traced circuit for enits associated switchhook, thereby to operate the hook switch SI04. When the hook switch SI04 is thus operated the transmitter I02 and the receiver I03 are effectively disconnected from the party subscriber line I30 and the previously traced loop circuit extending to the repeater 400 is interrupted, at the contacts I05. of the hook switch SI04, thereby to cause the line relay R450 in the repeater 400 to restore. Upon restoring, the line relay R450 interrupts, at the. contacts 452, the previously mentioned circuit for energizing the winding of the hold relay R460, thereby to i cause the latter relay to restore shortly thereafter. Also, the line relay R450 interrupts, at the contacts 45I, the previously traced loop circuit extending between the repeater 400 and the repeater selector 405, andthe previously mentioned circuit for energizing the left-hand winding of the answer relay R440. When the previously mentioned loop circuit'extending between the repeater 400 and the repeater selector 405 is thus interrupted, the answer relay-R440 in the ergizing the rotary magnet M352, and to condition the wiper 35I to be driven an additional step in the clockwise direction. When the pre-- viously traced circuit for energizing the rotary magnet M352 is interrupted the latter magnet restores, thereby to recomplete, at the contacts 353, the circuit for energizing the rotary magnet M352 and to drive the wiper 35I one step in the clockwise direction away from its home position.

In view of the foregoing explanation of the mode of operation of the rotary magnet M352, it will be understoodthat it is intermittently energized,

thereby to drive the wiper 35I of the meter switch 350 step by step in. the clockwise direction back into its home position. When the wiper 35I of the meter switch 350 is driven back into its home position the set of switch springs S354 is actuated into disengagement, thereby to interrupt a further point in the previously traced circuit for energizing the rotary magnet M352 in order posi' tively to arrest further operation thereof. At this time the meter switch 350 is completely released and restored to its normal position and the party line switch 320 is completely released. It is again noted that the wiper set of the party line switch 320 remains in engagement with the contact set terminating the trunk 410 extending to the repeater 400, as the party line switch 320 is of the nonhoming ty e.

Also, when ground potential 'is removed from the controlconductor C413 of the trunk 410, the

application of ground potential to the control conductor CI33 of the party subscriber line I30 is interrupted,- thereby to mark the last-men- 19 i tioned party subscriber line as idle to the party connectors 40I, etc., having access thereto. Also; at this time, the party subscriber line I20 is marked as idle to the party connectors 40I, etc., having access thereto, assuming that the subscriber at the called party subscriber substation 3I I has replaced, the receiver of the telephone instrument thereat upon its associated switchhook. Hence, the established connection between the calling fourth party subscriber substation 304, connected to the party subscriber line I30, and the called first party subscriber substation 3| I,

connected to the party subscriber line I20, is completely released at this time.

In view of the foregoing explanation of the mode of operation of the apparatus incorporated in the telephone system to extend a connection from the calling fourthparty subscriber substation 304, connected to the party subscriber line I30, to the called first party subscriber substation 3I I, connected to the party subscriber line I20,

it will be understood that a call may be extended apparent from the trunking plan, the directory numbers of the second, third and fourth party subscriber substations 3I2, 3I3 and 3I4, respectively, connected to the party subscriber line I20 are 3XX, 4XX and 5XX, or' 334, 434 and 534, respectively, in accordance with the foregoing ex-- ample. The party connectors 40I, 402, 403 and 404 respectively respond to the digits 1, 2, 3 and 4, in accordance with the foregoing example, to seize the party subscriber line I and respectively ring the seized party subscriber zine I20 with ringing currents of the following frequencies: 16 cycle, 33 cycle, 50 cycle and 66 cycle. The ringing currents of the respective frequencies mentioned projected over the called party subscriber line I20 operate the harmonic ringers at the respective first, second, third and fourth party subscriber substations 3I I, 3I2, 3I3 and3I4, connected to the party subscriber line I20.

Also, it will be understood that a call may be extended from the first, second or third party subscriber substations 30 I ,-302 or 303, respectively,

. connected to the party subscriber line I30, to any one of the party subscriber substations 3i I, etc., connected to the party subscriber line I20, in a manner substantially identical to that explained above. However, in the above-mentioned cases, when the calling devices at the respective first, second and third party subscriber substations 30 I, 302 and 303, respectively, connected to the party subscriber'line I30 are operated, no ground impulses, one ground impulse and two ground impulses are respectively transmitted therefrom in order to cause the corresponding operations of the meter switch'350, whereby the meters M305, M306 and M301 respectively corresponding to the first, second and third party subscriber substations 30I, 302 and 303, respectively, are operated in order to register the initiation of a call from the corresponding party subscriber substation.

Further, it will be understood that the extension of a call from one of the party subscriber substations, connected to a party subscriber line, to an individual subscriber substation, connected appropriate meter is controlled in the manner previously explained; the above-mentioned con- 20 nection is extended by way of one of the individual connectors. Also, it will be understood that the extension of a connection from an individual subscriber substation, connected to an individual subscriber line, to one of the party subscriber substations, connected to a party subscriber line, is substantially the same as that described above, whereby no metering is effected; the above-mentioned connection is'extended by way of the appropriate one of the 'party connectors 40I, etc. Finally, it is noted that the extension of a call from an individual subscriber substation, connected to an individual subscriber line, to an individual subscriber substation, connected to an individual subscriber line, is in accordance with conventional practice, whereby no metering is effected; the above-mentioned connection is extended by way. of one of the individual connectors.

Considering the extension of a call from a party subscriber substation, connected to a party subscriber line, such, for example, as the fourth party subscriber substation 304, connected to the party subscriber line I30, to the manual operator position 0, it is pointed out that the initiation and extension of the call from the calling fourth party subscriber substation 304 by, way of the party line switch 320, the trunk 410, the repeater 400 and the trunk 480 to the repeater selector 405,

are the same as that previously explained. At this time the subscriber at the calling'fourth party subscriber substation 304 dials the single digit 0, whereby the repeater selector 405 operates in order to seize an idle one of the trunks in the group extending to the manual operator position 0. The operator at the manual operator position 0 answers the call in accordance with conventional practice, whereby an established connection is completed between the calling fourth party subscriber substation 304, connected to the party subscriber line I30, and the called' manual operator position 0. In connection with the extension of the above-mentioned call, it is noted that the operation of the meter relay R420 in the repeater,400 and the meter switch 350, incident to the operation of the calling device I0 at the fourth party subscriber substation 304 to v transmit the digit 0, is the same as that previconnector.

scriber substation 304, connected to the party subscriber line I30, in view of the fact that the above-mentioned call is a free call which is not .metered. Thus it will be understood that, al-

though the meter switch 350 is set to select the meter M300 incident to the dialing of the digit 0 above-mentioned call to the manual operator position 0, in the manner previously explained,

' the meter M308 is not operated to meter the call when the operator at the manual operator'position 0 answers the call,

Considering now the extension of a' call from a party subscriber-substation, connected to a party subscriber line, such, for example, as the fourth party subscriber substation 304, connected to the party subscriber line I30, to the toll operator position I I0, it is pointed out that the initia the directorynumber H0, whereby the repeater selector 405 responds to the first digit 1 to select an idle special service selector, such, for example. as the special service selector- 405. The special service selector 40B responds to-the second digit 1 and drops back in a manner well understood, and

then responds to the third digit to select an idle trunk to the toll operator, position H0. The operator at the toll operator. position H0 answers the call in accordance'with conventional practice,

whereby an established connection is completed between the calling fourth party subscriber substation 304, connected to the party subscriber line I30, and the called toll operator position H0. In connection with the extension of the abovementioned call, it is noted that the operation oi the meterrelay R420 in the repeater 400 and the meter switch 350, incident to the operation of the calling device 10 at the fourth party subscriber substation 304 to'transmit the' first digit 1,

is the same as that previously explained. However, it is pointed out that the above-traced connection does not include a connector. Accordingly, when the operator at the toll operator position H0 answers the call, battery potential is not reversed over the trunk 400 to the repeater 400. Hence, the answer relay R440 in the repeater 4 00 does not operate in order to effect operation of the meter M301 individually associated with the calling third party subscriber substation 303, connected to the party subscriber line I30, in view of the fact that the abovementioned call is a iree call which is not metered. Thus it will be understood that, although the meter switch 350 is set to select the meter M301 incident to the dialing of the first digit 1 upon the calling device I0 at the calling fourth party subscriber substation 304 to extend the above-mentioned call to the toll operator position H0, in

' the manner previously explained, the meter M301 is not operated to meter the call when the operator at the toll operator position H0 answers the call.

In connection with the extension of the abovementioned call, ,it is noted that incident to the operation of the calling device l0 at the calling fourth party subscriber substation 304, connected to the party subscriber line I30, to transmit the first digit 1 to the line relay R450 in the repeater 400, this calling device l0 also sends two ground impulses to the meter relay R420 in the repeater 400, thereby to cause the meter switch 350 to select the meter M301 individually associated with the third party subscriber substation 303 instead of the meter M308 individually associated with the calling fourth party subscriber substation 304 as previously noted. However, the selection of the improper meter M301 by the meter switch 350 in connection with the extension of the abovementioned call is immaterial as the meter M301 is not operated, as explained above.

While there has been L scribed what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is contemplated to cover in the appended claims 22 all such modifications as fall within the true spirit and scope of the invention. What is claimed is: I

1. In an automatic telephone system, a party line, a plurality of stations on said party line; a calling device at each of said stations, the calling device at any calling one of said stations being selectively operable to transmit over said party line during a single operation thereof both,

a variable digit and an individual station signal, whereby the calling devices at said stations transmit over said party line different station signals incident to operation thereof, switching apparatus, means responsive to the transmission over said party line of one or more variable digits for correspondingly setting said switching apparatus .to extend the. call from the calling one of said stations, a plurality of registers individually corresponding to said stations, a register switch having access to said registers;-.and additional means controlled only in response to the first transmission over said party line of the station signal individual to the calling device at said one station for operating said register switch to select the one' of said registers corresponding to said one station.

2. In altelephone system; a line, a calling device associated with said line, said calling device being selectively operable to transmit over said line during a single operation thereof both a variable number of afirst type of impulses and a fixed number of a second type of impulses, a trunk circuit associated with said line and including a first line relay controlled by the first type of impulses transmitted over said line and a second line relay controlled by the second type of impulses transmitted over said line, a first control circuit governed by said first line relay, a second control circuit governed by said second line relay, and means governed by said first line relay for interrupting said second control circuit.

3. In a telephone system, a line, a calling device associated with said line, said calling device being selectively operable to transmit over said I line during a single operation thereof both a variable number of a first type of impulses and a fixed number of a second type of impulses, a

trunk circuit associated with said line, said trunk,

circuit including a first line relay provided with a winding connected to said line and controlled by the first type of impulses transmitted over said line and-a second line relay provided with two differential windings bridged across said line and controlled by the secondtype of impulses transmitted over said line, a first control circuit governed by said firstline relay, a second control circuit governed by said second'line relay, and means governed by said first line relay for interrupting said second control circuit,

4. In a'telephone system, a line, a calling device associated with said line, said calling device being selectively operable to transmit over said line during a single operation thereof both a variable digit and a fixed number of signal impulses, a trunk circuit associated with said line and including a first line relay controlled by the impulses of the digits transmitted over said line and a second line relay controlled by the signal impulses transmitted over said line, a first control circuit governed by said first line relay, a second control circuit governed by said second line relay,-and means governed by said first line relay at the conclusion of the first digit transmitcontrol circuit.

5. In a telephone system, a line, a calling device associated with said line, said calling device being selectively operable to transmit over said line during a single operation thereof'both a variable digit and a fixed number of signal impulses, a trunk circuit associated with said line, a switch and a counter associated with said trunk circuit, said trunk circuit including a first line relay controlled by the impulses of the digits transmitted ,over said line and a second line relay controlled by the signal impulses transmitted over said line, means governed by said first line relay i'or setting said switch, means governed by said second line relay for setting said counter, and means governed by said first line relay at the conclusion of the first digit transmitted over said line for arresting further setting of said-counter.

6. In an automatic telephone system, a party line, a plurality of stationson said party line, a calling device at each of said stations, the calling device at any calling one of said stations being selectively operable to transmit over said party line during a single operation thereof both 8. var-- iable digit and an individual fixed number of station impulses. whereby the calling devices at said stations transmit over saidwparty line ditterent numbers of station impulsesjncident to operation thereof, a repeater, means ij ponsive to the initiation of a call at anyone oi said stations for connecting said party line to said repeater, said repeater including a first line relay controlled by the impulses of the digit transmitted over said party lineand a second line relay controlledby the station impulses transmitted over said party line, a switch associated with said repeater, means governed by said first line relay for repeating to said switch the'impulses of the digit received over said party-line, thereby to set said switch in order to extend the call from said party line, a counter associated with said repeater, and means governed by said second line relay for setting said counter in accordance with the number of station impulses received over said party line, thereby to identify the particular calling one of said stations on said party line.

- JOHN ELLIS OSTLINE. 

